linux/include/drm/drm_dp_mst_helper.h
Dave Airlie 6b8eeca65b drm/dp/mst: close deadlock in connector destruction.
I've only seen this once, and I failed to capture the
lockdep backtrace, but I did some investigations.

If we are calling into the MST layer from EDID probing,
we have the mode_config mutex held, if during that EDID
probing, the MST hub goes away, then we can get a deadlock
where the connector destruction function in the driver
tries to retake the mode config mutex.

This offloads connector destruction to a workqueue,
and avoid the subsequenct lock ordering issue.

Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
2015-06-25 11:57:23 +10:00

520 lines
14 KiB
C

/*
* Copyright © 2014 Red Hat.
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that copyright
* notice and this permission notice appear in supporting documentation, and
* that the name of the copyright holders not be used in advertising or
* publicity pertaining to distribution of the software without specific,
* written prior permission. The copyright holders make no representations
* about the suitability of this software for any purpose. It is provided "as
* is" without express or implied warranty.
*
* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
* EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
* OF THIS SOFTWARE.
*/
#ifndef _DRM_DP_MST_HELPER_H_
#define _DRM_DP_MST_HELPER_H_
#include <linux/types.h>
#include <drm/drm_dp_helper.h>
struct drm_dp_mst_branch;
/**
* struct drm_dp_vcpi - Virtual Channel Payload Identifier
* @vcpi: Virtual channel ID.
* @pbn: Payload Bandwidth Number for this channel
* @aligned_pbn: PBN aligned with slot size
* @num_slots: number of slots for this PBN
*/
struct drm_dp_vcpi {
int vcpi;
int pbn;
int aligned_pbn;
int num_slots;
};
/**
* struct drm_dp_mst_port - MST port
* @kref: reference count for this port.
* @guid_valid: for DP 1.2 devices if we have validated the GUID.
* @guid: guid for DP 1.2 device on this port.
* @port_num: port number
* @input: if this port is an input port.
* @mcs: message capability status - DP 1.2 spec.
* @ddps: DisplayPort Device Plug Status - DP 1.2
* @pdt: Peer Device Type
* @ldps: Legacy Device Plug Status
* @dpcd_rev: DPCD revision of device on this port
* @num_sdp_streams: Number of simultaneous streams
* @num_sdp_stream_sinks: Number of stream sinks
* @available_pbn: Available bandwidth for this port.
* @next: link to next port on this branch device
* @mstb: branch device attach below this port
* @aux: i2c aux transport to talk to device connected to this port.
* @parent: branch device parent of this port
* @vcpi: Virtual Channel Payload info for this port.
* @connector: DRM connector this port is connected to.
* @mgr: topology manager this port lives under.
*
* This structure represents an MST port endpoint on a device somewhere
* in the MST topology.
*/
struct drm_dp_mst_port {
struct kref kref;
/* if dpcd 1.2 device is on this port - its GUID info */
bool guid_valid;
u8 guid[16];
u8 port_num;
bool input;
bool mcs;
bool ddps;
u8 pdt;
bool ldps;
u8 dpcd_rev;
u8 num_sdp_streams;
u8 num_sdp_stream_sinks;
uint16_t available_pbn;
struct list_head next;
struct drm_dp_mst_branch *mstb; /* pointer to an mstb if this port has one */
struct drm_dp_aux aux; /* i2c bus for this port? */
struct drm_dp_mst_branch *parent;
struct drm_dp_vcpi vcpi;
struct drm_connector *connector;
struct drm_dp_mst_topology_mgr *mgr;
struct edid *cached_edid; /* for DP logical ports - make tiling work */
};
/**
* struct drm_dp_mst_branch - MST branch device.
* @kref: reference count for this port.
* @rad: Relative Address to talk to this branch device.
* @lct: Link count total to talk to this branch device.
* @num_ports: number of ports on the branch.
* @msg_slots: one bit per transmitted msg slot.
* @ports: linked list of ports on this branch.
* @port_parent: pointer to the port parent, NULL if toplevel.
* @mgr: topology manager for this branch device.
* @tx_slots: transmission slots for this device.
* @last_seqno: last sequence number used to talk to this.
* @link_address_sent: if a link address message has been sent to this device yet.
*
* This structure represents an MST branch device, there is one
* primary branch device at the root, along with any others connected
* to downstream ports
*/
struct drm_dp_mst_branch {
struct kref kref;
u8 rad[8];
u8 lct;
int num_ports;
int msg_slots;
struct list_head ports;
/* list of tx ops queue for this port */
struct drm_dp_mst_port *port_parent;
struct drm_dp_mst_topology_mgr *mgr;
/* slots are protected by mstb->mgr->qlock */
struct drm_dp_sideband_msg_tx *tx_slots[2];
int last_seqno;
bool link_address_sent;
};
/* sideband msg header - not bit struct */
struct drm_dp_sideband_msg_hdr {
u8 lct;
u8 lcr;
u8 rad[8];
bool broadcast;
bool path_msg;
u8 msg_len;
bool somt;
bool eomt;
bool seqno;
};
struct drm_dp_nak_reply {
u8 guid[16];
u8 reason;
u8 nak_data;
};
struct drm_dp_link_address_ack_reply {
u8 guid[16];
u8 nports;
struct drm_dp_link_addr_reply_port {
bool input_port;
u8 peer_device_type;
u8 port_number;
bool mcs;
bool ddps;
bool legacy_device_plug_status;
u8 dpcd_revision;
u8 peer_guid[16];
u8 num_sdp_streams;
u8 num_sdp_stream_sinks;
} ports[16];
};
struct drm_dp_remote_dpcd_read_ack_reply {
u8 port_number;
u8 num_bytes;
u8 bytes[255];
};
struct drm_dp_remote_dpcd_write_ack_reply {
u8 port_number;
};
struct drm_dp_remote_dpcd_write_nak_reply {
u8 port_number;
u8 reason;
u8 bytes_written_before_failure;
};
struct drm_dp_remote_i2c_read_ack_reply {
u8 port_number;
u8 num_bytes;
u8 bytes[255];
};
struct drm_dp_remote_i2c_read_nak_reply {
u8 port_number;
u8 nak_reason;
u8 i2c_nak_transaction;
};
struct drm_dp_remote_i2c_write_ack_reply {
u8 port_number;
};
struct drm_dp_sideband_msg_rx {
u8 chunk[48];
u8 msg[256];
u8 curchunk_len;
u8 curchunk_idx; /* chunk we are parsing now */
u8 curchunk_hdrlen;
u8 curlen; /* total length of the msg */
bool have_somt;
bool have_eomt;
struct drm_dp_sideband_msg_hdr initial_hdr;
};
struct drm_dp_allocate_payload {
u8 port_number;
u8 number_sdp_streams;
u8 vcpi;
u16 pbn;
u8 sdp_stream_sink[8];
};
struct drm_dp_allocate_payload_ack_reply {
u8 port_number;
u8 vcpi;
u16 allocated_pbn;
};
struct drm_dp_connection_status_notify {
u8 guid[16];
u8 port_number;
bool legacy_device_plug_status;
bool displayport_device_plug_status;
bool message_capability_status;
bool input_port;
u8 peer_device_type;
};
struct drm_dp_remote_dpcd_read {
u8 port_number;
u32 dpcd_address;
u8 num_bytes;
};
struct drm_dp_remote_dpcd_write {
u8 port_number;
u32 dpcd_address;
u8 num_bytes;
u8 *bytes;
};
struct drm_dp_remote_i2c_read {
u8 num_transactions;
u8 port_number;
struct {
u8 i2c_dev_id;
u8 num_bytes;
u8 *bytes;
u8 no_stop_bit;
u8 i2c_transaction_delay;
} transactions[4];
u8 read_i2c_device_id;
u8 num_bytes_read;
};
struct drm_dp_remote_i2c_write {
u8 port_number;
u8 write_i2c_device_id;
u8 num_bytes;
u8 *bytes;
};
/* this covers ENUM_RESOURCES, POWER_DOWN_PHY, POWER_UP_PHY */
struct drm_dp_port_number_req {
u8 port_number;
};
struct drm_dp_enum_path_resources_ack_reply {
u8 port_number;
u16 full_payload_bw_number;
u16 avail_payload_bw_number;
};
/* covers POWER_DOWN_PHY, POWER_UP_PHY */
struct drm_dp_port_number_rep {
u8 port_number;
};
struct drm_dp_query_payload {
u8 port_number;
u8 vcpi;
};
struct drm_dp_resource_status_notify {
u8 port_number;
u8 guid[16];
u16 available_pbn;
};
struct drm_dp_query_payload_ack_reply {
u8 port_number;
u8 allocated_pbn;
};
struct drm_dp_sideband_msg_req_body {
u8 req_type;
union ack_req {
struct drm_dp_connection_status_notify conn_stat;
struct drm_dp_port_number_req port_num;
struct drm_dp_resource_status_notify resource_stat;
struct drm_dp_query_payload query_payload;
struct drm_dp_allocate_payload allocate_payload;
struct drm_dp_remote_dpcd_read dpcd_read;
struct drm_dp_remote_dpcd_write dpcd_write;
struct drm_dp_remote_i2c_read i2c_read;
struct drm_dp_remote_i2c_write i2c_write;
} u;
};
struct drm_dp_sideband_msg_reply_body {
u8 reply_type;
u8 req_type;
union ack_replies {
struct drm_dp_nak_reply nak;
struct drm_dp_link_address_ack_reply link_addr;
struct drm_dp_port_number_rep port_number;
struct drm_dp_enum_path_resources_ack_reply path_resources;
struct drm_dp_allocate_payload_ack_reply allocate_payload;
struct drm_dp_query_payload_ack_reply query_payload;
struct drm_dp_remote_dpcd_read_ack_reply remote_dpcd_read_ack;
struct drm_dp_remote_dpcd_write_ack_reply remote_dpcd_write_ack;
struct drm_dp_remote_dpcd_write_nak_reply remote_dpcd_write_nack;
struct drm_dp_remote_i2c_read_ack_reply remote_i2c_read_ack;
struct drm_dp_remote_i2c_read_nak_reply remote_i2c_read_nack;
struct drm_dp_remote_i2c_write_ack_reply remote_i2c_write_ack;
} u;
};
/* msg is queued to be put into a slot */
#define DRM_DP_SIDEBAND_TX_QUEUED 0
/* msg has started transmitting on a slot - still on msgq */
#define DRM_DP_SIDEBAND_TX_START_SEND 1
/* msg has finished transmitting on a slot - removed from msgq only in slot */
#define DRM_DP_SIDEBAND_TX_SENT 2
/* msg has received a response - removed from slot */
#define DRM_DP_SIDEBAND_TX_RX 3
#define DRM_DP_SIDEBAND_TX_TIMEOUT 4
struct drm_dp_sideband_msg_tx {
u8 msg[256];
u8 chunk[48];
u8 cur_offset;
u8 cur_len;
struct drm_dp_mst_branch *dst;
struct list_head next;
int seqno;
int state;
bool path_msg;
struct drm_dp_sideband_msg_reply_body reply;
};
/* sideband msg handler */
struct drm_dp_mst_topology_mgr;
struct drm_dp_mst_topology_cbs {
/* create a connector for a port */
struct drm_connector *(*add_connector)(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port, const char *path);
void (*destroy_connector)(struct drm_dp_mst_topology_mgr *mgr,
struct drm_connector *connector);
void (*hotplug)(struct drm_dp_mst_topology_mgr *mgr);
};
#define DP_MAX_PAYLOAD (sizeof(unsigned long) * 8)
#define DP_PAYLOAD_LOCAL 1
#define DP_PAYLOAD_REMOTE 2
#define DP_PAYLOAD_DELETE_LOCAL 3
struct drm_dp_payload {
int payload_state;
int start_slot;
int num_slots;
int vcpi;
};
/**
* struct drm_dp_mst_topology_mgr - DisplayPort MST manager
* @dev: device pointer for adding i2c devices etc.
* @cbs: callbacks for connector addition and destruction.
* @max_dpcd_transaction_bytes - maximum number of bytes to read/write in one go.
* @aux: aux channel for the DP connector.
* @max_payloads: maximum number of payloads the GPU can generate.
* @conn_base_id: DRM connector ID this mgr is connected to.
* @down_rep_recv: msg receiver state for down replies.
* @up_req_recv: msg receiver state for up requests.
* @lock: protects mst state, primary, guid, dpcd.
* @mst_state: if this manager is enabled for an MST capable port.
* @mst_primary: pointer to the primary branch device.
* @guid_valid: GUID valid for the primary branch device.
* @guid: GUID for primary port.
* @dpcd: cache of DPCD for primary port.
* @pbn_div: PBN to slots divisor.
*
* This struct represents the toplevel displayport MST topology manager.
* There should be one instance of this for every MST capable DP connector
* on the GPU.
*/
struct drm_dp_mst_topology_mgr {
struct device *dev;
struct drm_dp_mst_topology_cbs *cbs;
int max_dpcd_transaction_bytes;
struct drm_dp_aux *aux; /* auxch for this topology mgr to use */
int max_payloads;
int conn_base_id;
/* only ever accessed from the workqueue - which should be serialised */
struct drm_dp_sideband_msg_rx down_rep_recv;
struct drm_dp_sideband_msg_rx up_req_recv;
/* pointer to info about the initial MST device */
struct mutex lock; /* protects mst_state + primary + guid + dpcd */
bool mst_state;
struct drm_dp_mst_branch *mst_primary;
/* primary MST device GUID */
bool guid_valid;
u8 guid[16];
u8 dpcd[DP_RECEIVER_CAP_SIZE];
u8 sink_count;
int pbn_div;
int total_slots;
int avail_slots;
int total_pbn;
/* messages to be transmitted */
/* qlock protects the upq/downq and in_progress,
the mstb tx_slots and txmsg->state once they are queued */
struct mutex qlock;
struct list_head tx_msg_downq;
struct list_head tx_msg_upq;
bool tx_down_in_progress;
bool tx_up_in_progress;
/* payload info + lock for it */
struct mutex payload_lock;
struct drm_dp_vcpi **proposed_vcpis;
struct drm_dp_payload *payloads;
unsigned long payload_mask;
unsigned long vcpi_mask;
wait_queue_head_t tx_waitq;
struct work_struct work;
struct work_struct tx_work;
struct list_head destroy_connector_list;
struct mutex destroy_connector_lock;
struct work_struct destroy_connector_work;
};
int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr, struct device *dev, struct drm_dp_aux *aux, int max_dpcd_transaction_bytes, int max_payloads, int conn_base_id);
void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr);
int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state);
int drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, bool *handled);
enum drm_connector_status drm_dp_mst_detect_port(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port);
struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port);
int drm_dp_calc_pbn_mode(int clock, int bpp);
bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port, int pbn, int *slots);
int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port);
void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port);
void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
struct drm_dp_mst_port *port);
int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
int pbn);
int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr);
int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr);
int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr);
void drm_dp_mst_dump_topology(struct seq_file *m,
struct drm_dp_mst_topology_mgr *mgr);
void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr);
int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr);
#endif